Device for Slip Engagement of Large Tolerance Pipe and Method of Use

ABSTRACT

A coupling for a pipe comprises a housing adapted to accept a pipe within an interior portion of the housing and a cone disposed within the housing where, in embodiments, the cone is further adapted to accept the pipe and be allowed to yield rather than the pipe.

PRIORITY INFORMATION

This application claims the benefit of U.S. Provisional Application No.60/809,003, filed on May 26, 2006.

FIELD OF THE INVENTION

The invention relates to devices used for engaging pipes. Inembodiments, the invention more specifically relates to a device for usewith slip engagement of pipes such as large tolerance pipes.

BACKGROUND OF THE INVENTION

Current mechanically set Smart Flange Plus® connectors work on pipeswith a diameter tolerance of +1/−0%. However, the American PetroleumInstitute (API) pipe tolerance is as great as +/−1%. Providing a fullrange of API tolerances on Smart Flange Plus® connectors may lead tobuckling the pipe that is made to the high side tolerance (1%).

Further, the pipe load in the Smart Flange Plus® connector is staticallybalanced by the cone.

Additionally, cone material strength may be manipulated so that itsyield point and strain characteristics closely balance to that of thepipe. Thus, when a connector, e.g. a Smart Flange Plus® connector, ismade up and the pipe begins to yield prior to buckling, the cone itselfalso reaches yield. Further makeup yields the cone, not the pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present invention willbecome more fully apparent from the following description, appendedclaims, and accompanying drawings in which:

FIGS. 1-2 are views of embodiments, either in partial perspective or inpartial perspective cutaway, of embodiments of the invention.

FIG. 3 is a graph of loads on a pipe inserted into a coupling.

FIGS. 4 and 5 are flowcharts of embodiments of the disclosed methods.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In general, pipe is typically loaded in compression, but compression isunstable and the pipe has limited contraction before buckling. The coneis loaded in hoop, i.e. circumferential, tension which is stable.Typically, the cone can take high dialation strain.

Materials such as soft steels (e.g. A36, A105, C1020) have real strainelongations on the order of 30%. Austenitic stainless materials, e.g.3xx series, have strain elongations on the order of 40%.

Certain slips, as that term is understood by those of ordinary skill inthe pipe setting arts, comprise angled slip teeth where the slip teethangles are in the neighborhood of the friction angle, as that term isunderstood by those of ordinary skill in these arts. This keeps axialloads from the pipe during service from exerting radial loads on thecone.

Referring to FIG. 1, as the context requires herein, flange 10 generallycomprises flange 10 a and flange assembly 10 b. In a preferredembodiment, flange 10 a is a Smart Flange Plus® flange. Flange assembly10 b is as basically described herein. When the joint is made, flange 10a is made against flange assembly 10 b. As studs 17 tighten, a piston(generally shown at 18) pushes slips 300 into cone 200.

Flange 10 for pipe 12 in an embodiment is a coupling comprising housing100 adapted to accept pipe 12 within interior portion 111 of housing 100and cone 200 disposed within housing 100.

In certain currently contemplated embodiments, housing 100 may be madeof A105, A694, A350, 4130, and/or 4140 steel or the like.

Housing 100 may further comprise seal 120 disposed about interiorsurface 112 of housing 100 where seal 120 is adapted to conform to outersurface 13 of pipe 12 when pipe 12 is inserted at least partially intohousing 110. Seal 120 is made of a suitable material and may comprisenitrile (NBR), fluoroelastomer (FKM), or polyurethane (PUR), or thelike, or combinations thereof.

In certain embodiments, housing 100 further comprises limit ring 130disposed about interior surface 112 of housing 110 intermediate seal 120and cone 200. Limit ring 130 is also made of a suitable material and, incurrently contemplated embodiments, may comprise 4130 or 4140 alloysteel or the like.

Cone 120 is adapted to accept pipe 12 and be disposed about outerportion 14 of pipe 12 when a outer portion of pipe 12, e.g. exteriorsurface 14, is disposed within housing 100. In preferred embodiments,cone 200 comprises a material having a yield characteristic matched to apredetermined yield characteristic of pipe 12. Cone 200 is typicallydisposed at a predetermined position within housing 100 sufficient to bedisposed proximate an area of likely pipe buckling of pipe 12 when pipe12 is inserted into housing 100, e.g. area 15.

In certain contemplated embodiments of flange 10, cone 200 is preloadedin housing 100 under tension, e.g. cone 200 is in hoop tension as thatterm is understood by those of ordinary skill in these arts.

Additionally, cone 200 is typically adapted to tolerate high dilationstrain. In certain embodiments, cone 200 comprises steel having anelongation property in excess of 20%.

Referring additionally to FIG. 2, flange 10 may further comprise slip300, e.g. as part of flange assembly 10 b, where slip 300 furthercomprises internal teeth 310. At least one surface of a predeterminednumber of internal teeth 310 may comprise angled grip portion 312. Insuch embodiments, the angle of angled grip portion 312 may besubstantially equivalent to a friction angle sufficient to keep an axialload produced by pipe 12 from exerting a radial load on 200 cone pastsetting after flange 10 is set.

Slip 300, in currently contemplated embodiments, is made of hardened4140 or case-hardened 8620/8630 alloy steel or the like. In certainembodiments, slip 300 made from hardened 4140 steel is quenched andtempered hardened whereas slip 300 made from case-hardened 8620/8630alloy steel is carburized.

Flange 10 may further comprise slip 300 adapted to slidably engageexterior surface 14 of pipe 12 when pipe 12 is inserted into apredetermined portion of housing 100. Slip 300 is typically disposedintermediate cone 200 and exterior surface 14 of pipe 12.

In the operation of a preferred embodiment, referring to FIG. 3, slipengaging pipe 12 may be accomplished by manipulating material strengthof cone portion 200 (FIG. 1) of flange 10 b (FIG. 1) to its yield point.A predetermined strain characteristic of cone 200 is then manipulated tobalance pipe 12 (FIG. 1) to be engaged using repair connector and flange10 (FIG. 1) made up to pipe 12. In certain currently contemplatedmethods, cone 200 is loaded in tension.

Slip 300 (FIG. 1) may be positioned in-between cone 200 (FIG. 2) andpipe 12 (FIG. 2). In further embodiments using slip 300, an angle forslip teeth 300 (FIG. 2) may be determined which is substantiallyequivalent to a friction angle sufficient to keep an axial load producedby pipe 12 from exerting a radial load on cone 200 past setting and slip300 positioned to engage pipe 12 at the friction angle.

In a further embodiment of slip engaging a pipe, a buckling positionwithin an interior of housing 100 (FIG. 1) at which an inserted pipe,e.g. pipe 12 (FIG. 1), is likely to buckle when pipe 12 is inserted intohousing 100 and pipe 12 is under a predetermined load is determined.Cone 200 (FIG. 1), adapted to accept pipe 12 within interior portion 111(FIG. 1) of housing 100 proximate the buckling position, is disposedwithin housing 100. In typical embodiments, cone 200 comprises amaterial having a yield characteristic matched to a yield characteristicof pipe 12. Pipe 12 is inserted into an insertion portion of housing100, where the insertion portion is at least to the determined bucklingposition. Cone 200 is engaged about exterior surface 14 (FIG. 1) of pipe12 proximate the determined buckling position and a material strength ofcone 200 manipulated to its yield point. Cone 200 is then allowed toyield rather than pipe 12.

In certain currently contemplated methods, slip 300 (FIG. 1) may bepositioned in-between cone 200 (FIG. 1) and pipe 12 (FIG. 1).

Additionally, slip 300 (FIG. 1) may comprise angled slip teeth 310 (FIG.2) where the angle for slip teeth 310 may be substantially equivalent toa friction angle sufficient to keep an axial load produced by pipe 12(FIG. 1) from exerting a radial load on cone 200 (FIG. 1) past settingslip 300 positioned to engage pipe 12 at the friction angle.

It will be understood that various changes in the details, materials,and arrangements of the parts which have been described and illustratedabove in order to explain the nature of this invention may be made bythose skilled in the art without departing from the principle and scopeof the invention as recited in the claims.

1. A coupling for a pipe, comprising: a. a housing adapted to accept apipe within an interior portion of the housing; and b. a cone disposedwithin the housing, the cone further adapted to accept the pipe and bedisposed about an outer portion of the pipe within the housing, the conecomprising a material having a yield characteristic matched to apredetermined yield characteristic of the pipe.
 2. The coupling of claim1, wherein the housing further comprises a seal disposed about aninterior surface of the housing, the seal adapted to conform to an outersurface of the pipe inserted at least partially into the housing.
 3. Thecoupling of claim 2, wherein the housing further comprises a limit ringdisposed about the interior surface of the housing intermediate the sealand the cone.
 4. The coupling of claim 1, wherein the cone is preloadedin the housing under tension.
 5. The coupling of claim 4, wherein thewherein the cone is in stable hoop tension.
 6. The coupling of claim 1,wherein the cone is adapted to tolerate high dilation strain.
 7. Thecoupling of claim 1, wherein the cone material comprises steel having anelongation property in excess of 20%.
 8. The coupling of claim 1,further comprising a slip, the slip further comprising internal teethdisposed about a predetermined surface of the slip to engage apredetermined portion of the pipe when the slip is disposed about thepredetermined portion of the pipe.
 9. The coupling of claim 8, whereinthe slip teeth further comprise at least one angled grip surfaceportion.
 10. The coupling of claim 9, wherein the angle of the angledgrip portion is substantially equivalent to a friction angle sufficientto keep an axial load produced by the pipe from exerting a radial loadon the cone past setting after the coupling is set.
 11. The coupling ofclaim 1, further comprising a slip ring adapted to slidably engage anexterior surface of the pipe when the pipe is inserted into apredetermined portion of the housing.
 12. The coupling of claim 11,wherein the slip ring is disposed intermediate the cone and the exteriorsurface of the pipe.
 13. The coupling of claim 1 wherein the cone isdisposed at a predetermined position within the housing sufficient to bedisposed proximate an area of likely pipe buckling of the pipe when thepipe is inserted into the housing.
 14. A method of slip engaging a pipe,comprising: a. manipulating material strength of a cone portion of aflange to its yield point; b. manipulating a predetermined straincharacteristic of the cone to balance a pipe to be engaged using theflange; c. making up the flange to the pipe; and d. allowing the cone toyield rather than the pipe.
 15. The method of claim 14 furthercomprising loading the cone in tension.
 16. The method of claim 15,further comprising positioning a slip in-between the cone and the pipe.17. The method of claim 16, further comprising: a. determining an anglefor the slip which is substantially equivalent to a friction anglesufficient to keep an axial load produced by the pipe from exerting aradial load on the cone past setting; and b. positioning the slip toengage the pipe at the friction angle.
 18. A method of slip engaging apipe, comprising: a. determining a buckling position within an interiorof a housing at which a pipe is likely to buckle when the pipe isinserted into the housing and the pipe is under a predetermined load; b.disposing a cone adapted to accept the pipe within the interior of thehousing proximate the buckling position, the cone comprising a materialhaving a yield characteristic matched to a yield characteristic of thepipe; c. inserting a pipe into an insertion portion of the housing, theinsertion portion being at least to the buckling position; d. engagingthe cone about an exterior surface of the pipe proximate the bucklingposition; e. manipulating a material strength of the cone to its yieldpoint; f. manipulating a predetermined strain characteristic of the coneto balance the engaged pipe; and g. allowing the cone to yield ratherthan the pipe.
 19. The method of claim 18, further comprisingpositioning a slip in-between the cone and the pipe.
 20. The method ofclaim 19, further comprising: a. determining an angle for the slip whichis substantially equivalent to a friction angle sufficient to keep anaxial load produced by the pipe from exerting a radial load on the conepast setting; and b. positioning the slip to engage the pipe at thefriction angle.